The M16 is a lightweight, 5.56 mm, air cooled, gas operated, magazine fed assault rifle with a rolling bolt, actuated by direct impingement gas operation. The rifle is made from steel, aluminum, and composite plastic and polymer materials, and is the primary assault weapon for the United States military. The M16 entered U.S. Army service as the M16 A1 in South Vietnam in 1963 replacing the M14 rifle. Colt Industries, Inc. purchased the rights to manufacture a civilian version of the M16 (designated AR-15) from ArmaLite and currently uses the AR-15 designation only for semi-automatic versions of the M16 rifle. The AR-15 semi-automatic assault rifle has become very popular with hobbyists and gun collectors in the United States. The rifle serves various purposes from target shooting to hunting to varmint control. In that regard it has become a very popular to modify the AR-15 with a variety of accessories such as hunting rifle telescopic sights, bipods, infrared illuminators and night vision telescopic sights. In order to accommodate these accessories, the standard issue thermal setting plastic handguard on the AR-15 can be replaced by a variety of aftermarket milled aluminum multi-section handguards having accessory rails for mounting said accessories.
The following prior art patents are believed to be material and relevant to the examination of this application:
Pat. No.Publication DateNameUS2005/0241211Nov. 3, 2005SwanUS2005/0268513Dec. 8, 2005BattagliaUS2006/0026883Feb. 9, 2006Hochstrate et al.US2006/0236582Oct. 26, 2006Lewis et al.US2007/0017139Jan. 25, 2007LarueUS2008/0092422Apr. 24, 2008Daniel et al.4,536,982Aug. 27, 1985Bredbury et al.4,663,875May 12, 1987Tatro5,198,600Mar. 30, 1993E'Nama7,231,861June 2007Gauny et al.7,753,679July 2010Schuetz, Brian D.7,798,045September 2010Fitzpatrick et al.US2010/0236395Sep. 23, 2010Akhavan
These prior art handguards are often multi-segmental. Thus such accessory handguards are often difficult to machine to sufficiently high standards and tolerances such that unsightly gaps do not develop between mating surfaces while the handguards go through dramatic thermocycling during operation of the rifle.
Thus, a need exists for a handguard system for the AR-15 civilian assault rifle which is tolerant of minor size fluctuations and thermal expansions/contractions cycles without visible gaps in mating surfaces.